Dionysos is the god of theater, wine, and ecstasy. Fearing for the future of Athens as the city faces severe decline, he travels to the underworld to retrieve a deceased playwright whose wisdom might save his homeland. Despite his divine status, he is frequently indecisive, prone to fear, and quick to hide behind his enslaved companion when trouble arises. He disguises himself as the demigod Herakles to gain easy passage but immediately regrets the choice when he encounters his half-brother's enemies.

Xanthias is an enslaved man belonging to Dionysos, forced to accompany the god on a dangerous descent into the underworld. He is clever, courageous, and quick-witted, often demonstrating more practical competence than his divine master. Denied passage on Charon's boat because he did not fight in a recent naval battle, Xanthias must run around the river alone. He frequently capitalizes on Dionysos's cowardice, trading the Herakles disguise back and forth to his own advantage.

Euripides is a recently deceased Athenian tragedian known for writing clever, provocative dialogue and featuring ordinary or controversial characters in his plays. He is considered modern and progressive, prioritizing intellect and relatable domestic drama over grand mythological spectacles. He challenges the older poet Aischylos for the underworld's throne of tragedy, sparking a formal contest to determine the superior artist.

Aischylos is an older, established Athenian tragedian who holds the underworld throne for the greatest poet. He favors grandiloquent language, traditional martial values, and stories that inspire heroic behavior on the battlefield. He deeply resents Euripides's modern innovations, arguing that showcasing debauched characters and domestic quarrels actively degrades the moral character of Athenian citizens.

Herakles is a powerfully built demigod who previously traveled to the underworld to capture the guard dog Kerberos. He finds his half-brother's theatrical costume deeply amusing but provides the travelers with essential directions for their journey. He lists the horrific sights they will encounter, including a river of mud and excrement where perjurers and wrongdoers are submerged.

Charon is the grim ferryman of the underworld. He maintains strict rules regarding who may board his vessel, outright refusing entry to Xanthias because the slave did not fight for Athens in the battle of Arginousai. He holds no special reverence for gods, explicitly commanding Dionysos to row the boat himself.

Plouton is the ruler of the underworld. He acts as the ultimate authority in his domain, eventually taking charge of the chaotic situation involving Dionysos and Xanthias. He authorizes the high-stakes poetry contest between Aischylos and Euripides and appoints Dionysos to serve as the official judge.

A group of marsh-dwelling frogs who live in the watery boundaries of the underworld. They engage in a fierce, rhythmic vocal contest with Dionysos, their coordinated croaking severely disrupting the god's attempts to synchronize his rowing strokes.

A group of deceased souls who were initiated into the Eleusinian Mysteries during their mortal lives. They reside in a pleasant, well-lit area of the underworld, singing protective hymns to the gods while also loudly lampooning and mocking contemporary Athenian politicians and figures. They represent the diverse cross-section of society unified by religious rites.

The aggressive guard stationed at the entrance to Plouton's palace. He holds a massive grudge against Herakles for previously stealing the underworld's guard dog. When he sees Dionysos wearing the lion skin disguise, he unleashes a torrent of terrifying threats and runs to fetch reinforcements, causing Dionysos to soil himself in fear.

An enslaved man working in Plouton's household in the underworld. After the initial chaos settles, he spends time speaking privately with Xanthias. The two bond quickly over their shared delight in cursing, mocking, and gossiping about their respective masters behind their backs.

A woman running an establishment in the underworld. She recognizes the Herakles lion skin and immediately goes on the offensive, furious that Herakles previously ate an enormous amount of food at her inn without ever paying his bill. She recruits associates to help her enact violent revenge.